Sign Conventions
1
Sign Conventions
Since the pile head and ground surface may not be at the same elevation, the depth below the
ground surface is denoted as z and the depth below the pile head is denoted as x.
y
z
x
y
P
V
M
(+)
V
+y
deflection
(+)
(-)
𝑦
𝑥
Slope
−
M
x
P
Figure 1-1: Stress and deformation conventions
Note from Figure 1-1 that the positive stress conventions produce positive deflection in the yaxis, but the calculated slope is negative based on the orientation of the y and x axis.
2
Pile Orientation
The batter angle and slope angle are measured positive clockwise. The sliding depths, soil layer
thicknesses and groundwater table depth are measured along the local pile x-axis. For axially
loaded piles, the overburden pressure is calculated assuming zero slope angle. In other words, the
overburden pressure does not take into consideration the projected or actual ground surface
above each calculation point on a battered pile based on the slope angle.
Horizontal
Depth to Groundwater Table
(+)
Slope Angle, α
Layer 1 Thickness
Layer 2 Thickness
Pile
Vertical
Sliding Depths
(+)
Batter Angle, β